有没有办法在运行时间上优化此C程序

Question

its objective is to print all Fibonacci numbers up to the 93th

#include<stdio.h>

void main(){
  unsigned long long first=0,second=1,sum;
  printf("%llu,%llu",first,second);
  unsigned char hops=1;
  while (hops<93) {
    sum=first+second;
    printf(",%llu",sum);
    first=second;
    second=sum;
    hops++;
  }
  printf("\n");
}

Answer 1

Of course, you can. Just print precalculated string of numbers.

#include <stdio.h>
int main()
{
    puts("0,1,1,2,3,5,...");
    return 0;
}

Answer 2

In case you need to optimize the whole operation you need to think in terms of space and time complexity. From this point onwards you can think how better these can be.

Now printing the n numbers will ofcourse require an iteration which will be of time complexity O(n) . Is there any better way to do that? The thing is, if you do it multiple times you can get rid of addition by storing it somewhere. But that won't give you any better asymtotic time complexity improvement - rather you will face a O(n) space complexity - which will be an over head if printing is something you do only. (And ofcourse pre-computation have to be done).

So yes this solution is good enough to achieve what you are trying to do.

In case you need to scan some input - then I would ask you to go for getting inputs with getchar and then form the number from it (if needed). If you consider this in SPOJ or competitive programming judge server these tend to give better result. (Again time is lesser than that of scanf in large number of input cases - 10^7 etc).